A number of different systems and apparatus have been devised for extracting energy from the wave motion of water although very few have proved to be really practical. Examples of patents disclosing what will be referred to here, for shorthand purposes, as "wave motors", include U.S. Pat. Nos. 523,963 (Gerlach); 1,200,308 (Bunnell); 1,831,097 (David) and 1,025,929 (Snook), although this listing is not, nor is it represented to be, exhaustive. Briefly considering these patents, the Gerlach patent discloses a wave motor including a single paddle attached by a pulley to a toothed wheel and employing a pulley and cross-pulley arrangement. The Bunnell patent, while discussing wave motors in general, is actually directed to a "water motor" employing oppositely directed scoops. The David patent discloses a wave motor device including oppositely directed blades which collapse in one direction so that waves in that direction will not affect the operation of the device.
The Snook patent is perhaps the most relevant of the patents listed above insofar as the present invention is concerned in view of the disclosure therein of a wave motor including helical screws or fins which, as stated in the patent, are arranged so that the movement of the waves of the ocean will rotate the same thereby producing movement that may be transmitted to other mechanisms. The wave motor disclosed in the Snook patent suffers a number of disadvantages. For example, the construction disclosed in the Snook patent does not take into account the substantially simultaneous ebb and flow of the waves adjacent to the shore and because of this, the helical blades or fins can be subjected to oppositely directed thrusts at any one time. Moreover, provision is made for directly connecting the separate axles or shafts upon which the helical fins are located to rigid gears which can cause the shafts to rotate in opposite directions and produce an unworkable result. Thus, while, as will become evident from the discussion of the present invention hereinafter, the device of the Snook patent is broadly similar in certain regards to that of the present invention, the Snook device suffers important disadvantages which render its use impractical.